Laundry Dryer Heat Pump With Suction-Line Refrigerant Cooling
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Solution Overview
Problem
The existing heat pump systems in laundry dryers face inefficiencies due to unbalanced heating and cooling capacities, leading to increased refrigerant temperature and pressure, which results in higher compressor power consumption and longer drying times.
Innovation Solution
An additional heat exchanger is introduced between the outlet of a second heat exchanger and the inlet of the compressor, controlled by refrigerant and drying air temperatures to reduce refrigerant temperature before compressor suction, thereby decreasing compressor power requirements and improving heat pump performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the heat pump system operates with unbalanced heating and cooling capacities, then the heating power at the condenser increases, but the refrigerant temperature and pressure continuously increase, leading to higher compressor power consumption
Solution Approach 1:
An additional heat exchanger is introduced as an intermediary component in the refrigerant circuit, positioned between the condenser outlet and compressor inlet. This heat exchanger acts as a mediator to transfer excess heat from the high-pressure refrigerant to the low-pressure refrigerant, thereby cooling the refrigerant before it enters the compressor and reducing compressor power consumption while maintaining the heating capacity at the condenser.
Solution Approach 2:
The system changes the temperature and pressure parameters of the refrigerant by introducing an additional heat exchange step. The refrigerant is cooled and its pressure is adjusted in the additional heat exchanger before entering the compressor, which modifies the operating parameters to reduce the work required by the compressor while maintaining the desired heating output.
2Power
If the same drying air stream is cooled in the evaporator and heated in the condenser, then the heating capacity exceeds the cooling capacity, but this creates an imbalance that requires additional cooling components
Solution Approach 1:
The additional heat exchanger merges the high-pressure and low-pressure refrigerant streams, allowing heat transfer between them. This combines the cooling function with the existing heat pump cycle, balancing the heating and cooling capacities without requiring separate auxiliary cooling systems, thereby reducing overall system complexity.
Solution Approach 2:
The additional heat exchanger serves multiple functions: it cools the high-pressure refrigerant, pre-heats the low-pressure refrigerant, and balances the heating and cooling capacities of the heat pump system. This multi-functionality eliminates the need for separate components, simplifying the overall system design.
3Use of energy by moving object
If the refrigerant temperature is reduced before compressor suction, then the compressor power consumption decreases, but this requires additional heat exchange equipment
Solution Approach 1:
The additional heat exchanger merges the high-pressure and low-pressure refrigerant streams in a single component, achieving refrigerant cooling before compressor suction while utilizing the temperature difference between the two streams. This integrated approach cools the refrigerant without requiring separate auxiliary cooling equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances heat pump efficiency by reducing compressor power consumption and shortening the transitory phase while maintaining stable temperatures during the steady state phase, resulting in improved drying performance and energy savings.
Implementation Method 1
an additional heat exchanger is connected between the outlet of second heat exchanger and the inlet of the compressor... The additional heat exchanger is an additional heat exchanger between the refrigerant and an auxiliary cold source
Implementation Method 2
The compressor cooling fan blows ambient air onto the compressor case... heat is transferred to a source, which may be water or ambient air
Implementation Method 3
The evaporator is a heat exchanger at the low pressure side of the refrigerant circuit... where more heating capacity is available on the side of the refrigerant circuit
Implementation Method 4
The evaporator cools the drying air, after said drying air has passed the laundry drum
Implementation Method 5
The condenser is a heat exchanger at the high pressure side of the refrigerant circuit... The condenser heats up the air stream
Implementation Method 6
the condenser heats up the air stream, before the drying air is re-inserted into the laundry drum
Implementation Method 7
The compressor 14 compresses the refrigerant... The heating power at the condenser is in fact higher than the cooling power at the evaporator, since P condenser = P cooling + P compressor
Data Source
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AI summary
The present invention relates to a laundry dryer or a spinner-washer with a heat pump system. The heat pump system comprises a refrigerant circuit (10) for a refrigerant and a drying air circuit (12) for an air stream. The refrigerant circuit (10) includes a compressor (14), a first heat exchanger (16), expansion means (18) and a second heat exchanger (20) connected in series and forming a closed loop. The drying air circuit (12) includes the first heat exchanger (16), at least one air stream fan (30), a laundry drum (28) and the second heat exchanger (20) connected in series and forming a closed loop. The refrigerant circuit (10) and the drying air circuit (12) are thermally coupled by the first heat exchanger (16) and the second heat exchanger (20). The first heat exchanger (16) is provided for heating up the air stream and cooling down the refrigerant. The second heat exchanger (20) is provided for cooling down the air stream and heating up the refrigerant. The refrigerant circuit (10) includes at least one additional heat exchanger (22) connected between the outlet of second heat exchanger (20) and the inlet of the compressor (14) and is controlled or controllable by the temperature of the refrigerant in at least one position of the refrigerant circuit (10) and/or by the temperature of the drying air.